4.0.1 Release

build.gradle.kts

@@ -5,7 +5,7 @@ plugins {
 
 allprojects {
     group = "com.viaversion"
-    version = "4.0.1-1.17.1-rc1-SNAPSHOT"
+    version = "4.0.1"
     description = "Allow older clients to join newer server versions."
 }
 

common/src/main/java/com/viaversion/viabackwards/api/rewriters/LegacyBlockItemRewriter.java

@@ -174,7 +174,7 @@ public abstract class LegacyBlockItemRewriter<T extends BackwardsProtocol> exten
             tags.put(pos, tag);
 
             // Handle given Block Entities
-            if (pos.getY() < 0) continue; // 1.17
+            if (pos.getY() < 0 || pos.getY() > 255) continue; // 1.17
 
             ChunkSection section = chunk.getSections()[pos.getY() >> 4];
             if (section == null) continue;

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_12_2to1_13/packets/BlockItemPackets1_13.java

@@ -302,7 +302,7 @@ public class BlockItemPackets1_13 extends com.viaversion.viabackwards.api.rewrit
                         if (!provider.isHandled(id)) continue;
 
                         int sectionIndex = ((NumberTag) tag.get("y")).asInt() >> 4;
-                        if (sectionIndex < 0) {
+                        if (sectionIndex < 0 || sectionIndex > 15) {
                             // 1.17 chunks
                             continue;
                         }